Lubricants and polymeric additives therefor



United States Patent 3 198,739 LUBRECANTS ANDPULYMERIC ADDITIVES THEREFOR Harry F. Richards, Concord, alif., Stephen A. Herbert, Jr., Weston, Conn, and Robert 3. Moore, Orinda, Calih, assignors to Shell Gil Company, New York, N.Y., a corporation of Delaware No Drawing. Fiied Nov. 25, 1960, Ser. No. 71,403 4 Claims. (Cl. 252-56) This invention relates to improved mineral oil lubricating compositions and to an improved oil-soluble polyhydroxy-carboxylate copolymer therefor.

It is known that certain nitrogen-containing polymer compounds such as the commercial additives LOA-564 and 565 of Du Pont or Rohm and Haas 900 Series Acryloids such as Acryloid 917 or 966 as well as others, are good detergent additives for lubricating oil compositions. Such detergent nitrogen-containing polymeric additives lack wear-inhibiting properties and therefore oils which contain them must be supplemented with wear inhibitors or extreme pressure agents, etc. These materials and the acidic materials formed during engine operation tend to interact with the polymeric nitrogen-containing detergents, resulting in sludge and corrosion.

It is an object of the present invention to provide an improved oil-soluble detergent copolymer. Another object of the invention is to provide a lubricating oil composition possessing good detergent and antisluding properties. Still another object of the invention is to provide a lubricating oil composition containing a novel oxygencontaining copolymer which possesses good detergent and anti-sludging properties. Other objects in accordance with the invention will be apparent hereinafter.

It has now been discovered that these and other objects of the present invention may be accomplished by a new and novel copolymer having essentially a long linear hydrocarbon backbone chain and attached thereto, in a random or uniform fashion, two essential groups, the first being an oil-solubilizing ester group COOR where R is a C1040 alkyl radical, preferably a C alkyl radical, and the second being a -COOROH group where R is a C alkyl radical. Polymers of this type may be represented by the Formula I where R and R are alkyl radicals as defined above, Y may be a C alkyl radical or a polar radical such as an ester, amide, amine, or phosphate radical or the like, m and m; are Whole numbers of at least 2 each and u may be zero or a Whole number, the ratio of m to m may vary from 1:10 to :1, preferably from 5:1 to 2:1 and the ratio of m+m to n when n is a whole number may vary from 10:1 to 5:1, respectively. The molecular weight of the polymer varies from about one thousand to about one million, preferably from 10,000 to 500,000.

The first polymerizable monomer group includes acrylic and alkacrylic esters of aliphatic alcohols of at least 8 carbon atoms, preferably of from 10 to 20 carbon atoms, and include, inter alia, decyl acrylate, lauryl acrylate, stearyl acrylate, eicosanyl acrylate, docosanyl acrylate, decyl methacrylate, lauryl methacrylate, cetyl methacrylate, stearyl methacrylate, and the like, and mixtures thereof.

The other polymerizable group includes omega-hydroxyesters of acrylic or alkacrylic acid and dihydroxy alkanes which may be straight or branch-chain, preferably alpha,

3,198,739 Patented Aug. 3, 1965 decanoate, vinyl myristate, vinyl pentadecanoate, Vinyl.

palmitate, vinyl margarat'e, vinyl stearate, vinyl nonadecanoate, vinyl arachidate,-vinyl behenate, vinyl 4,5,6-trimethyldodecanoate, vinyl 6,8,9-triethyltridecanoate, vinyl IZ-hydroxystearate, vinyl 9,10-dihydroxystearate, vinyl chlorostearate, vinyl cyanostearate, vinyl acetylstearate;. vinyl ethers, vinyl dodecyl ether, vinyl tridecyl ether, vinyl tetracosyl ether, vinyl hexacosyl ether; allyl esters or ethers, allyl stearate, allyl dodecyl ether; amido esters, e.g., N-lauryl methacrylamide, N-stearyl methacrylamide, N,N'-di-.stearyl methacrylamide; vinylpyridines, e.g., 4- vinylpyridine, 2-methyl-5-vinylpyridine, vinylpyrrolidone, vinyl phosphonates and allyl phosphates, e.g., tn'methallyl phosphate, bis-chloroethyl vinyl phosphonate and and mixtures thereof.

The polymerization may be effected in the presence of a substantially inert liquid and in the presence of an oxygen-yielding catalyst at a temperature in the range of 50 to C., preferably between 6090 C.

Suitable liquid reaction media are various classes of hydrocarbons or their mixtures which are liquid and substantially inert under the polymerization conditions of the present process. Certain classes of aliphatic hydrocarbons can be employed as'a liquid hydrocarbon reaction medium in the present process. Thus may be employed various saturated hydrocarbons (alkanes and cycloalkanes) which are liquid under the polymerization reaction conditions and which do not crack substantially under the reaction conditions. Either pure alkanes or cycloalkanes or commercially available mixtures, freed of catalyst poisons, may be employed. For example, we may employ straight run naphthas or kerosenes containing alkanes and cycloalkanes. Specifically, we may employ liquid or liquefied alkanes such as n-pentane, n-hexane, 2,3-dimethylbutane, n-octane, isooctane (2,2,4- trimethylpentane), n-decane, n-dodecane, cyclohexane, methylcyclohexane, dimethylcyclopentane, ethylcyclohexane, decalin, methyldecalins, dimethyldecalins and the like.

Members of the aromatic hydrocarbon series, particularly the mononuclear aromatic hydrocarbons, viz., benzene, toluene, xylenes, mesitylene and xylene-p-cymene mixtures can also be employed. In addition, we may employ such aromatic hydrocarbons as ethylbenzene, isopropylbenzene, sec-butylbenzene, t-butylbenzene, ethyltoluene, ethylxylenes, hemimellitene, pseudocumene, prehnitene, isodurene, diethylbenzenes, isoamylbenzene and the like. Suitable aromatic hydrocarbon fractions can be obtained by the selective extraction of aromatic naphthas from hydroforming operations as distillates or bottoms, from cyclo stock fractions of cracking operations, etc.

'Also may be employed certain alkyl naphthalenes which are liquid under the polymerization reaction con recovered and the copolymer exhibited excellent detergent properties.

EXAMPLE V In a benzene solution containing 0.2% alpha,alpha'- azodiisobutyronitrile 2 mols of stearyl methacrylate, 1 mol of bischloroethylvinyl phosphonate and 1 mol of omega-hydroxyamyl methacrylate were added and the mixture was heated for 24 hours at 80 C. At the end of the reaction time an oil-soluble copolymer of stearyl methacrylate/bis chloroethylvinyl phosphonate/omegahydroxyamyl methacrylate havin a molecular weight of 150,000 was recovered and the copolymer exhibited excellent detergent properties.

, Following the above procedure, the following copolymers were prepared:

Omega-hydroxy 05-1 05-20 alkyl aerylate Temp., Molecular Example acrylate ester ester Optional monomer Solvent Catalyst 0. weight of polymer VI w-F ydroxyamyl acrystearyl methacrylate.. Benzene Ditertbutyl peroxide 90 250,000

Y a e. VII w-Hydlrotiyhexyl methd0 -d0 a, a-Azodiisobutyronitrile.. 80 150, 000

acry a VIII do ..do Triallyl phosphate" Heptene. do 80 100,000 IX w-Hydlrotxyamyl methdo Vinyl pyrrolidone..- Benzene do 80 200, 000

nary a e. X do Lauryl methacrylate" Vinyl stearate 1o do 90 250,000

The following examples are illustrative of the present invention.

EXAMPLEI In a benzene solution containing 0.2% alpha,a1pha'- azodiisobutyronitrile 2 mols of stearyl methacrylate and 1 mol of omega-hydroxyamyl methacrylate were added and the mixture was heated for 24 hours at 80 C. At the end of the reaction time an oil-soluble copolymer of stearyl methacrylate/ omega hydroxyamylmethacrylate having a molecular weight of 155,000 was recovered and the copolymer exhibited excellent detergent properties.

EXAMPLE II In a benzene solution containing 0.2% alpha,a1pha'- azodiisobutyronitrile 1.1 mols of stearyl methacrylate, 1.9 mols of lauryl methacrylate and 1 mol of omegahydroxyamyl methacrylate were added and the mixture was heated for 24 hours at 80 C. At the end of the reaction time an oil-soluble copolymer of stearyl methacrylate/omega-hydroxyamyl methacrylate having a molecular weight of 400,000 was recovered and the copolymer exhibited excellent detergent properties.

EXAMPLE III In a benzene solution containing 0.2% alpha,alpha'- azodiisobutyronitrile 2 mols of stearyl methacrylate and 1 mol of 1,B-dirnethyl-omega-hydroxyamyl methacrylate were added and the mixture was heated for 24 hours at 80 C. At the end of the reaction time an oil-soluble copolymer of stearyl methacrylate/1,3-dimethyl-omega hydroxyarnyl methacrylate having a molecular weight of 155,000 was recovered and the copolymer exhibited excellent detergent properties.

EXAMPLE IV In a benzene solution containing 0.2% alpha,alpha- :azodiisobutyronitrile 2 mols of stearyl methacrylate, 1 mol Z-rnethyl-S-Vinylpyridine and 1 mol of omegahydroxyamyl methacrylate were added and the mixture was heated for 24 hours at 80 C. At the end of the reaction time an oil-soluble copolymer of stearyl methacrylate/ 2 methyl-S-vinylpyridine/ omega hydroxyamyl methacrylate having a moiecular weight of 100,000 was When desired, additional improvements with respect to oxidation stability and scufiing inhibition can be imparted to the oil compositions containing the copolymers of this invention by incorporating small amounts (0.01%- 2%, preferably 0.1%-1%) of phenolic antioxidants such as alkylphenols, e.g., 2,6-ditertbutyl-4-methylphenol or p,p'-methylene bisphenols such as 4,4-rnethylene bis (2,6-ditertbutylphenol) or arylamines such as phenylalpha-naphthylamine and mixtures thereof. Anti-scuifing agents include organic phosphites, phosphates, phosphonates and their thio-derivatives, such as C alkyl phosphites, or phosphonates, e.g., diand tributyl, octyl, lauryl, stearyl, cyclohexyl, benzyl, cresyl, phenyl, phosphites or phosphates, as well as their thio-derivatives, P S -terpene reaction product, e.g., P S -pine oil reaction product and alkali metal salts thereof such as a potassium salt of a P S -terpene reaction product, phosphonates such as dibutyl methanephosphonate, dibutyl trichloromethanephosphonate, dibutyl monochloromethanephosphonate, dibutyl chlorobenzenephosphonate, and the like. The full esters of pentavalent phosphorous acids such as triphenyl, tricresyl, trilauryl and tristearyl ortho-phosphates or potassium salt of P S -terpene reaction product are preferred.

The polymeric additives of this invention improve various mineral oil products by the incorporation of a minor amount (0.01% to 5%, preferably 0.1% to 3% by weight) of the additive. Thus, they may be used to improve transformer oils, turbine oils, mineral lubricating oils, industrial oils and the like. Suitably such lubricating oils range from SAE 5W viscosity grade .to SAE 140 grade and are derived from parafiinic, naphthenic or asphaltic base crudes. Representative oils are refined high viscosity index mineral oils having a viscosity of F of 100 to 250 SUS. A typical mineral lubricating oil (X) of this type had the following properties:

Gr. API, 60/60 F 32 Flash, F. 370 Viscosity Index (Dean and Davis) 93 Viscosity, SUS at 100 F. 103

5 The following non-ash compositions are representative of this aspect of the invention.

Lubricating compositions of this invention are particularly applicable for high temperature, high speed use as in aviation engines, automotive engines, truck engines Composition A: Percent wt. 11 d 1 Example I copolymer 2 ustna zi 5 e c arm as our mven ion: i sgiil g 011 (X) Balance 1. A mineral lubricating oil composition consisting es- 1e c 01 mer 2 sentially of a major amount of mineral lubricating oil Mineral lubricgfig on 6 Balance and from about 0.01% to by weight of an oil-soluble Com osition copolymer of a C1240 alkyl methacrylate and an ester of g 1e Co 01 mar 2 methacrylic acid and an alpha, omega C alkanediol in Minergl z z oil Balance the ratio of 1:10 to 10: 1, respectively, said copolyiner hav- Com osition ing a molecular weight of from 10,000 to 500,000.

g 1e Co 01 2 2. A mineral lubricating oil composition consisting es- Minergl lubricagny on Balance sentially of major amount of mineral lubricating Oil and Com osition g 1 from about 0.01% to 5% by weight of an oil-soluble g 1e co olymer 2 copolymer of a C1240 alkyl methacrylate and an ester of Mineral lubricgfing oil Balance methacrylic acid and 1,5-pentanediol in the ratio of 1:10 Composition to 10:1, respectively, said copolymer having a molecular Example copolymer 3 weight of from 10,000 to 500,000. 4 4, methy1ene bis 2 ig f g zg gg g' s 1 3. A mineral lubricating oil composition consistlng es- Mineml lubricating (aviation oil 65 sentially of a major amount of mineral lubricating oil grade) Balance and from about 0.01% to 5% by weight of an oil-soluble comnosifion copolymer of stearyl methacrylate and an ester of methajixamnle I'copdymer 5 crylic acid and 1,5-pentanediol in the ratio of 1:10 to 4 4, methy1ene his, g ';gg g gfl ggf 0 5 10:1, respectively, said copolymer having a molecular Tricresyl phosphate weight of from 10,000 to 500,000. Mineral lubricating 5 7i Balane 4. A mineral lubricating oil composition consisting esi "f "i sentially of a major amount of mineral lubricating oil in order to demonstrate the utility and nnproved propand from about 0.01% to 5% by weight of an oil-soluble erties of this invention, the c0mpos1t1ons identified in copolymer of stearyl methacrylate, lauryl methacrylate, Table I were tested in the Chevrolet V8 Sludgmg Test, an ester of methacrylic acid and 1,5-pentanediol in the modified EX-3 test described in CRC Progress Report ratio of 1:10 to 10:1, respectively, said copolymer having No. 3, June 1, 1957, and the results were as follows: a molecular weight of from 10,000 to 500,000.

Table I P 1: il 1? Composition Active group Piston B Total 11 Total 0 Final 4 r iii g 0 i varnish varnish sludge rating plugging increase at 1. Composition A (present invention) -OO5OH 9.3 45.1 70.1 94.8 5 13 CompositionB (present invention) OC5OH 8.3 40.8 72.7 86.2 5 13 F 2. Mineral oil (X) plus 2% copolymer stearyl OOCCOH 8.3 40.0 60 77.6 13

methncrylate and monomethacrylate ester of I hexylene glycol (M.W. 143,000). C C

3. Mineral oil (X) plus 2% coploymer stearyl -O-C2OH 8.8 41.6 63.6 81.5 16 23 methacrylate and hydroxyethyl methacrylate (M.W. 230,000).

4. Mineral oil (X) plus 2% copolymer of vinyl CH2CH2 8.5 40.1 70.2 84.0 25 27 pyrrolidone and lauryl methacrylate (M.W. 500,000). CE C=O 5. Mineral oil (X) plus 2% copolymer of lauryl 8.5 39.5 61.0 77.6 79 23 methacrylate, stearyl methecrylate, 2-methyl-5- vinylpyridine (M.W. 500,000).

N/ CH3 8 10, perfect. b 50, perfect. 100, perfect. a 100, perfect.

References Cited by the Examiner UNITED STATES PATENTS 2,892,790 6/59 Stuart et a1 25256 2,892,792 6/59 Stewart et al 25256 2,892,819 6/59 Stewart et a1. 25256 X 2,913,439 11/59 Bondi et a1 25256 X 2,927,013 3/60 Lowe 44-62 2,949,445 8/60 Blake 26086.1 2,980,658 4/61 Ham 26086.1 2,994,663 8/61 Lowe et a1. 252-56 FOREIGN PATENTS 590,443 1/60 Canada.

DANIEL E. WYMAN, Primary Examiner. JULIUS GREENWALD, JOSEPH R. LIBERMAN,

Examiners. 

1. A MINERAL LUBRICATING OIL COMPOSITION CONSISTING ESSENTIALLY OF A MAJOR AMOUNT OF MINERAL LUBRICATING OIL AND FROM ABOUT 0.01% TO 5% BY WEIGHT OF AN OIL-SOLUBLE COPOLYMER OF A C12-20 ALKYL METHACRYLATE AND AN ESTER OF METHACRYLIC ACID AND AN ALPHA, OMEGA C5-7 ALKANEDIOL IN THE RATIO OF 1:10 TO 10:1, RESPECTIVELY, SAID COPOLYMER HAVING A MOLECULAR WEIGHT OF FROM 10,000 TO 500,000. 